In practice we have never seen a pump suction reducer as FOB though the
suction line is coming from the top in most cases in a refinery/process
plant. So as per your mail below if FOB is acceptable then we have to
rethink about the pump suction routing philosophy. So can you please
explain the reason why FOB is also recommended.
Also could you explain the 5D straight length requirement in the Pump suction line and the potential problems in case it is not followed.
Regards
"Jacques
Chaurette" To:
<PipingDesign@yahoogroups.com>
<jchaurette@fluide cc: (bcc: VAIBHAV
DEVDHAR/JAMNAGAR/RIL)
design.com> Subject: Re: [PipingDesign]
Eccentric Reducers on Pump Suctions Redux - FOT/FOB
Importance: Normal Sender's OU:
Reliance |------------------|
02/26/05 07:56 AM
| [ ] Confidential |
Please respond to
|------------------|
PipingDesign
The Pump Handbook actually recommends both situations, depends on whether the fluid is coming horizontal or from the bottom (FOT) or if it is coming from the top (FOB).
Jacques
www.fluidedesign.com
<a href="http://www.mcnallyinstitute.com/CDweb/p-html/p015.htm">http://www.mcnallyinstitute.com/CDweb/p-html/p015.htm</a>
"Make sure eccentric reducers are not installed upside down at the pump suction. The top of the reducer should go straight into the suction flange."
"Use eccentric reducers rather than concentric reducers at the pump suction. Concentric reducers will trap air. Be sure the eccentric reducer is not installed up side down."
"Be careful to install the eccentric reducer with the straight side up to prevent trapping air at the pump suction."
<a href="http://www.fluidedesign.com/download-free/guidel_pump_syst-extract.pdf">http://www.fluidedesign.com/download-free/guidel_pump_syst-extract.pdf</a>
"Always use an eccentric reducer at the pump suction when a pipe size
transition is
required. Put the flat on top when the fluid is coming from below or
straight (see
Figure 1) and the flat on the bottom when the fluid is coming from the
top. This will
avoid an air pocket at the pump suction and allow air to be evacuated."
[This text is followed by a graphic showing a *flat-on-bottom* eccentric reducer directly connected to a pump suction with suction line coming in from the top (as if feeding the pump from a piperack). The image is credited to "The Pump Handbook published by McGraw-Hill.]
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[Non-text portions of this message have been removed] Received on Fri Feb 25 23:16:00 2005
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